The present invention is in the field of resistant window systems providing improved protection for individuals and equipment against respective injury and damage by fragments of the window pane flying into the protected structure. The invention is also concerned with some specific mechanisms for use in conjunction with blast resistant window systems in accordance with the invention. The term xe2x80x9cwindowxe2x80x9d refers to a variety of window types, e.g. swingable/tiltable casement windows, fixed windows, curtain walls, etc.
Hereinafter in the specification and claims, the terms xe2x80x9cwindowxe2x80x9d and xe2x80x9cwindowsxe2x80x9d are interchangeably used with door and doors, respectively.
Casement windows typically comprise a rectangular framework consisting of a frame anchored within an opening in a wall and sash swingably mounted thereon with locking means preventing unintending opening thereof. Casement windows are either or both swingable inwards or outwards and at times, are also tiltable.
Fixed windows are those windows wherein the framework is fixed within an opening in a wall and which are not capable of swinging or tilting about one or more axis. Sliding windows are those windows which are slidingly received and concealed within an opening in the wall or, alternatively, slidable along a suitable railing parallel to the wall.
Curtain walls are those glass panels which are used, in particular, for decoration and concealing structural elements of buildings, creating a building""s envelope. Curtain walls also protect the building structure from weather effects and damage. The design and construction of curtain walls is such that vertical loads are not transferred between floors of a building.
The present invention is directed to all types of windows and doors and accordingly, the terms xe2x80x9cwindow sashxe2x80x9d and xe2x80x9cwindow framexe2x80x9d may be used alternatively, depending on the context and the type of window or door described.
Curtain walls are nowadays often used. Such curtain walls are constructed of large glass panes supported to transversely extending frame members (referred to in the art as mullions and transums), enveloping the construction of a building and providing a pleasing and esthetic appearance of the building.
Windows which are designed to resist blasts caused, for example, by an explosion, are so designed such that the window frame and window sash remain in place although, deformation thereof is allowed up to a certain extent. In some cases, the window pane may detach from the frame at low energy, so as not to fly into the room. In such windows, the window pane itself is blast resistant too and is typically, although not explicitly, made of several layers of glass with reinforcing material embedded therebetween, such as, for example, flexible polymeric material. Generally, blast resistant windows are designed also to prevent noxious gases from entering a confined room space.
Several patents deal with reinforcing means for ensuring that the window sash remains in place during a blast. Other patents deal with methods for reinforcing the window pane. Such reinforcing may be by embedding suitable wiring or elastomeric material.
However, during a blast, the glass component of the window pane breaks, and although remains attached to the reinforcing layers of the window pane, the entire window deforms and might forcefully disengage from the supporting window sash and fly into the room, causing severe damage to equipment or injury to personnel within that room.
It is an object of the present invention to provide blast resistant window systems in which the window pane is prevented from blowing forcefully into the room upon an external blast or upon applying kinetic energy thereto, e.g. by crowds pushing against the window pane or by ballistic impact such as bullets or shrapnel of bombs. This main object is achieved by absorbing the deformation and displacement of the window pane in a direction perpendicular to the window pane and converting it into mechanical energy which is either dampened or, preferably, wasted e.g. by converting it into heat or mechanical work. The wasted and dampened energy is transferred to the window framework (window sash or window frame or frame members in case of a curtain wall) or to construction elements of the building, e.g. wall or columns, by a suitable energy dispensing system.
The term xe2x80x9cenergy dispensing devicexe2x80x9d used hereinafter in the specification and claims denotes any mechanical arrangement or mechanism suitable for converting one form of mechanical energy into another form e.g. displacement work into heat or into other mechanical work such as plastic deformation, elastic deformation, sheer, etc.
As already pointed out hereinabove, the present invention is applicable to any type and form of window or door, mutatis mutandis.
In accordance with a first aspect of the present invention there is provided a blast resistant window system fitted with an energy dispensing device.
In accordance with a first aspect of the present invention there is provided a blast resistant window system comprising a reinforced window pane defining an in-side and an out-side and being supported by a window framework for mounting at an opening in a wall; the window system characterized in that it further comprises at least one pane-engaging member transversely extending adjacent an in-side surface of the window pane and secured at respective ends thereof to opposite framework elements or to opposite wall portions; each of the at least one pane-engaging member is fitted with at least one energy dispensing device for converting axial force within the pane-engaging member into mechanical work.
The energy dispensing device may be a separate device or may constitute a component of the framework.
In accordance with a preferred embodiment the window is a casement window and the framework comprises a sash mounted on a window frame fixed at the opening in the wall; the at least one pane-engaging member being secured to and extending between either or both pairs of top and bottom rails, and hanging and shutting stiles of the window sash. By a modification, when the window constitutes part of a curtain wall, the framework comprises a plurality of substantially transversely extending frame members, and wherein the at least one pane-engaging member is secured to respective such frame members.
Where the window constitutes part of a curtain wall, at least some of the pane-engaging member may extend within frame members whilst other pane-engaging members extend transversely across the window pane. This arrangement provides also improve reinforcement of the frame members of the curtain wall. This arrangement may be applied also to other types of windows, as can be readily realized.
The pane-engaging member is typically a cable or cord made for example of steel wire, advanced technology material such as complex material, etc. retaining their flexibility.
In accordance with any of the above embodiments, the at least one energy dispensing device may be fitted anywhere along the respective pane-engaging member or (instead or in addition) at or adjacent respective ends thereof.
At least some of the one or more energy dispensing devices may be concealed within the sash or window frame member (in case of casement windows etc.) or within the frame members (in case of a curtain wall).
The energy dispensing device is adapted for wasting mechanical energy and converting it into different forms of energy for preventing the window pane from flying into the protected room. This may be achieved by directing the energy to the framework of the window. Alternatively, the energy dispensing device is adapted for dampening the energy and wasting it in a different form, e.g. heat or elastic, gained energy.
By one preferred embodiment, the energy dispensing device is adapted for converting axial displacement of the pane-engaging member into plastic deformation or into mechanical sheer. By one specific design, the energy dispensing device may be part of the framework. In accordance with a different embodiment, the energy dispensing device comprises an elastic member for temporarily gaining and then releasing the energy. Alternatively, the energy dispensing device comprises a piston and cylinder assembly wherein axial displacement energy is converted into heat.
In accordance with one specific embodiment, the energy dispensing device comprises an elastic member having a longitudinal axis coaxial with that of the pane-engaging member; the elastic member bears at one end thereof against an end plate of the pane-engaging member, and at an opposed end thereof against a corresponding member of the framework.
In accordance with a different specific embodiment the energy dispensing device is a tubular element formed with one or more substantially radially extending recesses, wherein applying axial force thereon entails plastic deformation of the tubular element. In accordance with a modification of this embodiment the tubular element bears at a first end thereof against a member of the framework, and at a second end thereof it is integral with or bears against a respective end plate of the pane-engaging member.
In accordance with a preferred design, the energy dispensing device comprises a tubular element formed with at least one substantially radially extending rib, and a sheering member adapted for sheering the at least one rib upon coaxial displacement of at least one of the tubular element and the sheering member with respect to one another.
Still preferably one of the tubular element and the sheering member is coupled to an end of the pane-engaging member or to a respective framework member, and the other of the tubular element and the sheering member is articulated to the other of an end of the pane-engaging member and a respective framework member, respectively.
In accordance with a specific design the sheering member is ring-like shaped and coaxially extends with respect to the tubular element, adapted for consecutively sheering the radial ribs.
The arrangement of the window system in accordance with the invention is such that deformation or displacement of the window pane in an inbound direction, entails engagement of the window pane with the pane-engaging member giving rise to axial force within the pane-engaging member. This may also be achieved wherein deformation or displacement of the window pane in a direction substantially perpendicular to the plane of the window pane entails engagement thereof with the pane-engaging member to generate an axial, tension force in the pane-engaging member.
In accordance with a second aspect of the invention there is provided an energy dispensing device for use in conjunction with a blast resistant window system, the device comprising a first member having a longitudinal axis and a second member; at least one of said first and second members being fixedly attachable to a respective end of a window pane-engaging member; one or both of the first and second members comprises at least one energy wasting member extending along the longitudinal axis, said at least one wasting member bearing against a cooperating surface of the respective other first and second member; wherein axial displacement of the first and second members with respect to one another is converted into a different form of work.
According to one specific design, one or both of the first and second members constitute component elements of the framework of the window.
The first and second members may be a piston and cylinder, respectively, adapted for converting displacement energy into wasted heat. By one specific embodiment a restraining arrangement is provided for dampening the axial displacement of the piston and cylinder, e.g. a viscous liquid provided in the cylinder and aperture of restricted size for restraining air escape from the cylinder, etc.
By a different embodiment of the second aspect of the invention, the first and second members may be elastic members which elastically deform upon applying axial displacement thereto and which tend to retain their original shape after a while.
In accordance with a preferred embodiment of the second aspect of the invention, the axial displacement energy is converted into plastic deformation or sheeting of the one or more energy wasting members. Preferably, the one or more energy wasting members are one or more radially extending ribs adapted for sheer or plastic deformation.
In accordance with a specific design the one or more energy wasting member is a tubular member formed with a plurality of radial slits adapted for plastic deformation upon applying axial force thereto. By still a specific design, the energy wasting member is adapted for consecutive wasting of mechanical work wherein the energy wasted along the axial axis increases along with increase of axial displacement of the first and second members with respect to one another.
By still a specific design of the preferred embodiment the first member is a core element formed with a plurality of laterally extending ribs and the second member is a sheering member receiving the first member and formed with an opening having a sheering surface bearing against a first of said ribs, said opening sized to admit access of the core element and sheer one or more of the ribs. Preferably, the sheering member is ring-like shaped.
Still preferably, the sheering member is a housing accommodating at least one pair of orientation opposed, axially extending first members. In accordance with one specific design the sheering member is a housing accommodating at least one pair of orientation opposed, axially extending first members.
The housing may be fitted for fixedly attaching to a fixed construction element of the framework or wall wherein the first member attached to the pane-engaging member is axially displaceable.
Preferably, the pane-engaging member transversely extends adjacent and parallel to a blast resistant window pane, or within a profiled framework element.
In accordance with still a different aspect of the present invention there is provided a blast resistant window system comprising a reinforced window pane supported by a framework assembled of a plurality of tubular profiled members and being receivable within an opening in a wall; a frame support member extending within the profiled members with at least one energy dispensing device fitted thereon; the frame work comprises a plurality of openings through which the frame support member projects for engagement with corresponding anchors fixed to the wall.
In accordance with a preferred embodiment of the latter aspect, the window is fixed casement window and wherein the frame support member is made of a substantially flexible material.
Preferably there is further provided a transversal member having its respective ends articulated to the frame support member; said transversal member being a pane-engaging member extending adjacent an in-side face of the window pane, or a frame support member extending through a corresponding transversal tubular profiled member.
It will be appreciated that the energy dispensing device used in the blast resistant window system in accordance with the latter aspect of the present invention is in compliance with the energy dispensing devices disclosed hereinabove and in further detain in the specification.
Still preferably, there may be provided at least one tensioning member extending within the profiled members, for tensioning the frame support member.
The term xe2x80x9cwall portionxe2x80x9d as used herein in the specification and claims refers collectively to structural elements, including walls, foundation structures of a building (such as columns, etc.) floor and ceiling.
The reinforced window pane used in accordance with any of the aspects of the present invention is typically a bullet, attack and blast resistant material typically made of sandwiched material, offering protection against vandalism (physical attack) kinetic energy of bullet and shrapnel, of blast, etc.